This invention relates generally to the alignment of wheels on vehicles and more particularly to a method and apparatus for locating a vehicle steering wheel at a centered position so that the vehicle wheels can be aligned when the steering wheel is in a proper position.
During the alignment of vehicle wheels, it is important that the steering wheel of the vehicle be in a centered position before the vehicle wheels are aligned into their calibrated position specified by the manufacturer. Some vehicles are manufactured to have their front wheels in a toe-in position while other vehicles are toe-out. In either case, the wheels are symmetrically situated about the center axis of the vehicle so that the vehicle moves straight forward when the steering wheel is in the centered position and the wheels are properly aligned.
Typically, during alignment operations, a vehicle steering wheel is calibrated by first centering the steering wheel within the vehicle and then aligning the wheels of the vehicle. If the steering wheel is not properly calibrated in a centered position when the vehicle wheels are aligned, later operation of the vehicle with the steering wheels in a centered position will cause the vehicle to turn because the wheels will not be in proper alignment.
One known device for centering a vehicle steering wheel includes a bubble level and an assembly for engaging the molding of the vehicle windshield. The level is aligned with respect to the steering wheel. If the level does not indicate the correct position, the operator adjusts the position of the steering wheel until the level reads correctly. After a correct reading, the operator can indicate that alignment of the wheels should proceed. The usefulness of this apparatus is limited because it relies on human accuracy for reading the level and adjusting the steering wheel to a correct position. This system also does not prevent human error from occurring when the vehicle wheels are aligned prior to the centering of the steering wheel.
There are other more recent devices that serve the same purpose. For example, U.S. Pat. No. 4,342,279 to Seko discloses a device for detecting steering angle and direction. This device includes two contacts which are affixed to a steering column and adapted to be engaged by a movable contact when the steering wheel is turned. Upon contact, a pulse signal is produced and is sent to an electric circuit for detecting rotation.
In another system disclosed in U.S. Pat. No. 4,893,413 to Merrill et al., the apparatus includes a centering unit for sensing the position of the steering wheel with respect to a predetermined centering position. Arms coupled to the centering unit are linked together via cams so that pivotable movement of one arm causes the other to pivot in a symmetrical fashion. Rollers and flanges at the end of each arm abut against the front of a steering wheel on which the device is mounted. The device is installed by spreading the arms until the rollers are spaced to be received in the crotches formed between the spokes and steering wheel. A spring provides a downward biasing force to maintain the device in the installed position. When so mounted, the steering wheel can be moved until the electronic level indicates that the steering wheel is leveled and the wheels subsequently aligned.
Each of these prior art steering wheel centering devices are difficult to use since they require additional mounting means to work with steering wheels of different sizes and spoke configurations.
Accordingly, a need remains for a steering wheel centering device that can be easily adapted for use with a variety of steering wheels.